1. Field of the Invention
The invention relates to the field of video and audio signal monitoring and test equipment, and in particular concerns a signal processor with analog composite video inputs, serial digital video inputs (compliant with ITU-R BT.601 SMPTE 259M standards at 270 Mb/s, 50 Hz and 60 Hz field rates, also called CCIR 601) as well as stereo analog audio inputs. The signal processor is operable selectively and/or simultaneously to display video images, graphic video waveform information, graphic vector data and audio information, including audio phase and multi-channel audio signals, in high resolution form. The invention is useful in connection with audio and graphics production, mixed format and video production and post production facilities, and can replace multiple pieces of test equipment such as waveform monitors, vectorscopes, audio test sets and various format video monitors.
2. Description of the Related Art
Standard video signals are generally displayed on either television sets or composite video monitors in color or black and white. For color, the standard color composite video signal is an analog signal that electrically represents the brightness or luminance, saturation and color hue or chrominance of a complete video picture or frame, divided into sequential individual picture elements (pixels) of a raster scanned display. A pixel is the smallest discrete area of a television or video picture, each including adjacent red, blue and green phosphors. In addition, the signal includes synchronizing information associated with controlling raster scanning, such as blanking and maintaining the correct phase relationship between the signal and deflection of the electron beam for scanning accurately over the respective colored parts of the successive pixels.
Monitors compliant with various video standards such as NTSC, PAL and SECAM are available and display a video image in an interlaced format having specific timing. For example, an NTSC compliant composite video signal is displayed with 525 lines per frame at 30 frames per second. Each frame is composed of two interlaced fields of 262.5 lines completed at a field rate of 59.94 Hz.
Three basic types of synchronizing information are contained in the signal, namely horizontal sync pulses at the line rate, vertical sync pulses at field rate and a color burst during horizontal blanking. The color burst typically controls a phase locked loop and provides a frequency and phase reference for correctly decoding the color information by illuminating the correct colored phosphors with the cathode ray electron beam at the correct time.
Video production equipment advantageously includes various forms of video and audio signal monitoring and measurement equipment useful to verify the integrity of the signal being processed, for example for adjusting equipment to certain standards when processing a test pattern or for generally monitoring characteristics of the program. The composite graphic video waveform can be viewed graphically, for example, using an oscilloscope triggered by the horizontal sync to provide a two dimensional representation of the video signal in Cartesian coordinates (X axisxe2x80x94time, Y axisxe2x80x94amplitude) when processing a test pattern having vertical color bars. Alternatively a modified oscilloscope with specific time bases and amplitude scales is used.
The color content of the video signal is represented by phase relationship to the subcarrier synchronized to the color burst. Accordingly, color information is advantageously displayed graphically in a polar plot using a vectorscope. A vectorscope is generally a specialized, oscilloscope operable to display a Lissajous pattern in which both the X and Y axis of the display represent luminance information (e.g., red minus luminance plotted against blue minus luminance). The vectorscope is useful in setting or monitoring timing, phase and amplitude parameters of a video signal to match standard color test patterns.
Typical stereo and/or mono audio information which accompanies a television video signal is generally displayed on moving needle galvanometers or LED bar displays with scales calibrated in dB. Multi-channel xe2x80x9csurround soundxe2x80x9d audio information advantageously displayed with multiple bar displays with scales calibrated in dB. For example, the Tektronix AV601 provides AES/EBU Digital Audio Monitoring capabilities including Audio Level, Phase and Time Code Displays.
Test instruments such as the Videotek VTM-100, VTM-100D and the Tektronix WVR500 provide for the simultaneous display of video image information, waveform, vector and audio graphic display information in interlaced format on an NTSC or PAL monitor. The use of standard interlaced displays for simultaneous display of such information severely limits the clarity and detail of the video images, rasterized waveforms, vectorscope and audio graphic display information.
It would be desirable to provide a simple and efficient means to display NTSC. PAL, SECAM and High Definition (i.e., as specified in SMPTE 292M) video images, waveforms, vectorscope and audio graphic display information with increased clarity and detail, and preferably selectively and simultaneously.
The present invention is directed to an audio-video signal processor with two analog composite video inputs, two serial digital video inputs (compliant with ITU-R BT.601 and SMPTE 259M standards at 270 Mb/s, 50 Hz and 60 HZ field rates) as well as two stereo analog or digital audio inputs. The processor controls simultaneously display of video images, waveform, vector and audio information in high resolution form, each in a quadrant of standard computer monitor.
In another inventive aspect of the present invention is directed to an audio-video signal processor having dual serial digital inputs (e.g., 720p, 1080i, and 1080p/24sf serial digital input formats), an audio graphic display for 5.1 or 7.1 channels of input audio display and monitoring, XGA (1024xc3x97768) output, a display aspect ratio of either 4:3 or 16:9, A-B parade/overlay inputs (synchronous and same format) and filters, Timecode input (LTC and VANC) with on screen display, Analog, AES/EBU and embedded audio inputs with analog monitoring, 8 Analog, AES/EBU and embedded audio inputs and associated displays. The processor controls simultaneously display of video images, waveform, vector and audio information (audio phase and improved multiple channel audio graphic displays) in high resolution form, each in a quadrant of standard computer monitor.
The invention is useful in connection with graphics, mixed format and video production and post production facilities including broadcasting, and serves all the functions of waveform monitors, vectorscopes, various types of audio test sets and standard video monitors, providing substantial cost reduction and increased convenience.